In U.S. Pat. Nos. 4,293,400, 4,378,276, 4,872,959, and 5,043,050 there are described electrolytic treatment devices which apply an electric field to a liquid which flows between electrodes incorporated in the devices. In some of these devices, the electrodes are metal tubes or pipes whose sizes are predetermined by the sizes of pipe which are commercially available. In the device disclosed in the later patent the electrodes are flat, and while this apparatus provides a substantial advantage over the earlier tubular designs, it was found that when this invention was embodied in very large treatment devices it was difficult to adequately seal the edges of the unit particularly after long periods or use and shutdown. Moreover, uneven liquid flows between the electrodes sometimes causes plugging on the side with the lower flow rate followed by a resistive bridge of the plugged material which can lead to heat buildup in the treatment unit.
While the above referenced patents disclose electrolytic treatment devices which demonstrate the successful use of an electromotive force to drive chemical reactions and which are useful in the purification of liquid solutions, they have the added advantage of enabling the control of the reactions by permitting adjustment of the spacing between the electrodes, the level of the voltage applied across the electrodes and thus the strength of the current passing through the solution being treated. Moreover, the chemicals in the solution available to be reacted in the treatment device can be controlled. However, even though these prior art systems thus provide for a substantial amount of flexibility in their operation, it would be desirable to provide an electrolytic treatment system which could be operated to favor the removal of a high percentage of a particular material in the solution being treated.